Simple and very fast event bus. The EventBus library is a convenient realization of the observer pattern. It works perfectly to supplement the implementation of MVC logic (model-view-controller) in event-driven UIs
General concept
EventBus was created because I want something easy to use and faster than CCNotificationCenter from cocos2d-x library. Of course C++11 support was mandatory at that moment.
EventBus main goals:
- Fast
- Easy to use
- Strongly typed
- Free
- tiny (~37 KB)
- Decouples notification senders and receivers
- on every platform you need (cross-platform)
Presentation google docs
You can checkout use_case/
If you want to play with sample online checkout this link: wandbox.org
- Store bus
// store it in controller / singleton / std::shared_ptr whatever you want
auto bus = std::make_shared<EventBus>();- Define events
namespace event // optional namespace
{
struct Gold
{
int goldReceived = 0;
};
struct OK {}; // Simple event when user press "OK" button
}- Subscribe
// ...
dexode::EventBus::Listener listener{bus};
listener.listen([](const event::Gold& event) // listen with lambda
{
std::cout << "I received gold: " << event.goldReceived << " 💰" << std::endl;
});
HudLayer* hudLayer;
// Hud layer will receive info about gold
hudLayer->listener.listen<event::Gold>(std::bind(&HudLayer::onGoldReceived, hudLayer, std::placeholders::_1));- Spread the news
//Inform listeners about event
bus->postpone(event::Gold{12}); // 1 way
bus->postpone<event::Gold>({12}); // 2 way
event::Gold myGold{12};
bus->postpone(myGold); // 3 way- Process the events
bus->process();Checkout tests or use cases for more examples. Or create issue what isn't clear :)
EventBus can be added as ADD_SUBDIRECTORY to your cmake file.
Then simply link it via TARGET_LINK_LIBRARIES
Example:
# No tests/benchmarks target won't be added. Root CMakeLists is for development.
ADD_SUBDIRECTORY(path/to/EventBus/lib)
ADD_EXECUTABLE(MyExecutable
main.cpp
)
TARGET_LINK_LIBRARIES(MyExecutable PUBLIC Dexode::EventBus)
Also if you want you can install library and add it at any way you want. Eg.
mkdir -p lib/build/
cd lib/build
cmake -DCMAKE_BUILD_TYPE=Relase -DCMAKE_INSTALL_PREFIX=~/.local/ ..
cmake --build . --target install
# OR
make && make install
Now in Release/install library is placed.
Or, you can install the library through your package manager (dpkg, rpm, etc). E.g.
mkdir -p lib/build/
cd lib/build
# For most RH-based Distributions
cmake -DCMAKE_BUILD_TYPE=Relase -DCPACK_GENERATOR="RPM" ..
# For most Debian-based Distributions
cmake -DCMAKE_BUILD_TYPE=Relase -DCPACK_GENERATOR="DEB" ..
# Or for both of them
cmake -DCMAKE_BUILD_TYPE=Relase -DCPACK_GENERATOR="RPM;DEB" ..
cmake --build . --target package
# Or
make package
# For most Debian-based systems
sudo dpkg -i EventBus*.deb
# For most RH-based systems
sudo rpm -i EventBus*.rpm
# OR
sudo yum install EventBus*.rpm
I have prepared some performance results. You can read about them here Small example:
check10NotificationsFor1kListeners 263 ns 263 ns 2668786 sum=-1.76281G
check10NotificationsFor1kListeners_CCNotificationCenter 11172 ns 11171 ns 62865 sum=54.023M
checkNotifyFor10kListenersWhenNoOneListens 18 ns 18 ns 38976599 sum=0
checkNotifyFor10kListenersWhenNoOneListens_CCNotificationCenter 127388 ns 127378 ns 5460 sum=0
Please report here issue / question / whatever, there is chance 99% I will answer ;)
If you have any questions or want to chat use gitter.
// TODO
- staakk for fixing windows ;) 53d5026
- kuhar for his advice and suggestions for EventBus
- swietlana for English correction and support ;)
- ruslo for this great example: https://github.com/forexample/package-example
EventBus source code can be used according to the Apache License, Version 2.0. For more information see LICENSE file
If you don't like to read to much here is sumup about license Apache 2.0